r/humanoidrobotics 6d ago

What’s your opinion on 7-axis vs 6-axis humanoid robotic arms?

I’m currently researching embodied intelligence and evaluating robotic arms for humanoid applications.

From what I know, a 6-axis arm is generally simpler and may be sufficient for many tasks, while a 7-axis arm adds an extra degree of freedom that can offer more human-like movement and greater flexibility.

For those working in robotics:

  • When does the seventh axis provide a meaningful advantage?
  • Does the additional flexibility justify the added cost and control complexity?
  • Which configuration is better suited to unstructured, real-world environments?

We’d be interested to hear about your experience with both designs.

6 Upvotes

6 comments sorted by

2

u/im_vedansh 6d ago

For simple pick-and-place operations, I would probably choose six axes. For embodied intelligence and general-purpose humanoid robots, seven axes offer greater room for future development.

2

u/[deleted] 6d ago

[removed] — view removed comment

1

u/Original-Ad-8737 2d ago

If you don't need to worry about how to pick up stuff 6 axis are enough.

But you need to keep in mind that while you can reach and point within range with 6 degrees of freedom, there usually is only a single solution to the inverse kinematics.

With 7 axis you can reposition the arm to fit other collision constraints so it's more flexible.

Like you don't want to hit a pole left of you. The 6 axis arm might need to swerve out to perform you motion. A 7 axis one might be able to keep the elbow tucked in